Large aperture uniaxial crystal refractive index uniformity measurement apparatus and method thereof

Abstract

The invention relates to a large aperture uniaxial crystal refractive index uniformity measurement apparatus and a method thereof. A collimating mirror, a polarizer and a semitransparent mirror are sequentially arranged in the emitting light path of a laser; the semitransparent mirror reflects and transmits light incident to the semitransparent mirror to respectively form reflected light and transmitted light; a convergent mirror is arranged in the path of the reflected light and converges the reflected light into an integrating sphere power meter; a beam compressing system object lens, a beam compressing system ocular lens and a Shack-Hartmann wavefront sensor are arranged in the path of the transmitted light; a large aperture uniaxial crystal to be measured is placed between the polarizer and the semitransparent mirror; and a computer is respectively connected with the integrating sphere power meter, the Shack-Hartmann wavefront sensor and the large aperture uniaxial crystal to be measured. The apparatus and the method can realize the large aperture uniaxial crystal refractive index uniformity measurement without being restricted by wavelength or being influenced by extraneous environment airflow and vibration, and well guarantees the measurement precision.

Description

Technical field [0001] The invention belongs to the field of optics, and relates to a crystal refractive index uniformity measuring device and method, and in particular to a large-aperture uniaxial crystal refractive index uniformity measuring device and method based on a Shaker-Hartmann wavefront sensor. Background technique [0002] With the construction of the Shenguang III host device in my country, large-diameter uniaxial crystals are used as frequency conversion elements in the inertial confinement fusion system, which has a vital impact on the final output energy of the system. Especially the large-aperture KDP crystal, which is a key material for frequency doubling devices and electro-optical switches in high-power lasers, and its material quality and component processing quality greatly affect the realization of the final indicators of the device. Structural defects in the crystal growth process or photoelastic effects caused by internal stress, crystal gravity, crystal ...

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Problems solved by technology

The disadvantages of this method are: 1) Relying on the large-caliber interferometer imported from abroad, which is expensive and the measurement cost is high; 2) The output center wavelength of the interferometer is fixed, and it is impossible to measure the uniformity of the uniaxial crystal refractive index in the actual working band; 3 ) The polarization state of the output laser of the interferometer is fixed, and the switching of the orthogonal polarization state cannot be realized; 4) The measurement needs to place a polarizer at the test port of the output laser, and the extinction ratio of the polarization state greatly affects the contrast of the interference fringes; 5) This method cannot deduct the error introduced by the tilt change introduced by the interferometer phase shifter to the measurement of the uniformity of the refractive index of the uniaxial crystal; 6) This method is susceptible to ambient air flow disturbance and vibration

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